Photo lock system

ABSTRACT

An access control system for actuating a latch or other device when the appropriate key member is inserted. A receptacle with photocells at first and second stations with a transparency at the first station. A film strip key member with a complementary transparency and an average transmission or gray scale on the remainder of the film matching that of the complementary transparency. Detector circuitry having the photocells connected in the input for actuating a latch or initiating an alarm as a function of the particular key member inserted.

United States Patent 1191 Zink [111 7 3,896,345 July 22, 1975 PHOTO LOCKSYSTEM [22] Filed: Sept. 3, 1974 Tinsley 21 A l.-N0.Z 502 851 1 pp 57ABSTRACT An access control system for actuating a latch or other [if]3l7/ligks2B5g/75/gz) device when the pp p y member is inserted. Areceptacle with photocens at first and Second [58] Field of Search317/134; 250/555, 556,

trons w1th a transparency at the first station. A film strip key memberwith a complementary transparency and an average transmission or grayscale on the re- [56] References Cited mainder of the film matching thatof the complemen- UNITED STATES PATENTS tary transparency. Detectorcircuitry having the pho- 3,5l4,611 5/1970 Cohen 250/557 tocellsconnected in the input for actuating a latch or Baskerville et a1. analarm as a function of the particular key 3,787,714 1/1974 Resnick etal. 317/134 member inserted 3,793,565 2/1974 Smith 317/134 3,835,2979/1974 lnoue et al.... 250/557 9 Claims, 3 Drawing Figures T0 Accesstpfy 5,351,759

3,845,362 10/1974 Roe 317/134 Primary Examiner-.L. T. Hix

Attorney, Agent, or Firm-Harris, Kern, Wallen &

' II7 MA.C.

PATENTED JUL 2 2 ms 70 A C6555 CONTROL DE V/ CE MECHANICAL LA g EAL.ADJ.

L A MP 5UPPL Y PHOTO LOCK SYSTEM This invention relates to accesscontrol of an electrooptical nature intended as a replacement for theconventional mechanical and magnetic types of locks and access controlsystems presently in use.

Some optical access systems have been proposed, including those shown inUS. Pat. Nos. 3,773,862; 3,619,060 3,769,514; 3,818,190; 3,797,936;3,584,958; 3,457,013; 3,124,636; 1,135,919; and 1,775,794, but none ofthese prior art devices have the structure or the advantages of thesystem as disclosed and claimed herein.

The new system provides an optical or photographic coding which can haveunlimited variations and which can be highly personalized. In oneembodiment, a transparency such as a photographic negative is installedin the receptacle and a complementary transparency such as a positive ofthe same photograph is utilized in the key number, with access beingobtainable only when the complementary transparencies are positionedadjacent to each other.

The present system also providesa two-step configuration which not onlygives increased protection against unauthorized entry, but which alsocan provide an alarm or other indication whenentry is attemptedutilizing an improper key member.

The preferred embodiment incorporates a receptacle with photocells orother radiation sensors at first and second stations, with atransparency at the first station. Positioning the complementarytransparency at the first station will normally provide an access signalfor actuating a latch or other control device. However, the

complementary transparency of the key member as well as other portionsof the key member must pass the second photocell and if the averagetransmission of the complementary transparency and the averagetransmission of the other portions of the key member do not match apredetermined value, generation of the access signal will be blocked.While reference is made herein to generation of an access signal andoperation of a latch, it will bereadily understood that the system ofthe invention can be utilized for other purposes and that basically itserves to indicate whether or not the key member being inserted isproperly coded for the particular receptacle. I

Accordingly. it is an object of the invention to provide a new andimproved control system of the type described above. It is a specificobject of the invention to provide such a control system incorporatingtwo detection stations, and utilizing complementary transparencies foridentification. Other objects, advantages, features and results willmore fully appear in the course of the following description. Thedrawing merely shows and the description merely describes a preferredembodiment of the present invention which is.given by way ofillustration or example.

In the drawing:

FIG. 1 illustrates an access control system incorporating the presentlypreferred embodiment of the invention;

FIG. 2 is a perspective view illustrating the relationship of thereceptacleand key member; and

FIG. 3'is' an exploded view illustrating the construction of thereceptacle of FIG. 1.

- The system illustrated in FIG. 1 includes a receptacle 10, a keymember 11, a control circuit 12, and a latch 13.

A typical receptacle construction is shown in greater detail in FIG. 3and includes plates l8, 19 carried in spaced relation by sides 20, 21defining a slot 22 between the plates for receiving the key member 11. Astop 23 is mounted between the plates at one end thereof. The receptaclecomponents typically are made from plastic sheet stock, cut to size andcemented together.

Openings 26, 27 are provided in the plate 19 for receiving photocells28, 29 resepectively, which function as radiation sensors. Similaropenings (not shown) are provided in the plate 18 for receiving lamps30, 31 which serve as radiation sources. As shown in FIG. I,

lamp 30 directs radiation across the slot 22 to the sensor 28 and lamp31 directs radiation across the slot to sensor 29. The lamps areconnected to a power source via leads 32. Of course, other radiationsources and sensors can be utilized as desired and in one alternativeconfiguration, a single lamp can serve as a radiation source for bothsensors.

The system includes complementary transparencies, typically a negativeand a positive of a photograph. One of the transparencies, the negative35 in the embodiment illustrated, is mounted in the receptacle at one ofthe openings for the photocell 28 and lamp 30. The other transparency,in this embodiment a positive 36, is carried by the key number 11. Inthe preferred embodiment illustrated, the key member is a strip of 16 mmfilm with the positive printed directly on the film. The image of thepositive is positioned on the key member so as to be exactlysuperimposed over the image of the negative 35 when the key member isfully inserte into the receptacle.

The remainder of the key member, or at least those portions which movepast the opening 27 as the key member is inserted, has an averageradiation transmission characteristic substantially the same as that ofthe positive 36. This is readily accomplished by providing an overallgray shade for the remainder of the film strip equal to the averagedensity of the positive. The film strip forming the key member may beprotected by laminating between plastic cover sheets.

In the control circuit 12, the photocell 28 is connected in series witha variable resistor 40 across a voltage source at terminals 41, with thejunction of the photocell and resistor connected as an input to anintegrated circuit 42, typically a Signetics NE 555 2 or a Motorola MC1555. The circuit 42 provides an access signal on output line 43indicating that a proper key member has been inserted into thereceptacle. The access signal may be utilized for any purpose includingactuation of an access control device, an indicator, a recording deviceor the like. In the embodiment illustrated, the access signal isutilized to actuate the latch '13 by energizing a solenoid 45 through atransistor amplifier 46, with the solenoid functioning to remove a bolt47 from a jamb 48.

nected to an alarm or indicator or recorder orthe like to indicate thatan attempt has been made tofoperate the system by an improperly codedkey member.

The system is initially adjusted by inserting the properly coded keymember part way into the receptacle, with the key member at the sensor29 but not at the sensor 28. The resistor 51 is varied to provide a zerovoltage at input terminal 2 of the integrated circuit 52, with noblocking signal on the output line 53. Resistor 40 is adjusted toprovide a voltage at input terminal 2 of integrated circuit 42 such thatthere is no access signal on the output line 43 except when there is noradiation at sensor 28. The system is now ready for use.

A person seeking access inserts a key member into the slot of thereceptacle. As the key member passes the sensor 29, the resistance ofthe photocell increases and the voltage at terminal 2 of circuit 52decreases. If the gray scale or average transmission characteristic ofthe inserted key member is proper, the voltage at terminal 2 will bezero. When the key member is fully inserted, the transparency 36 will bein line with'the transparency 35 providing a complete blocking of lighttransmission to the sensor 28..The resistance of the sensor 28 goes upand the voltage at terminal 2 of integrated circuit 42 goes downsufficiently to provide an output at line 43, which for the specificcircuits illustrated is about +9 volts. This is the access signal,indicating that a properly coded key member has been inserted into thereceptacle.

However, if the gray scale or average transmission of the key member isless than that for the properly coded key member, less light will arriveat the photocell 29 resulting in a darker field, with a higherresistance for the photocell and a lower or negative voltage at terminal2 of integrated circuit 52, which produces an output on line 53. Thisoutput is the blocking signal and typically is about +9 volts. Theblocking signal can be utilized to actuate an alarm. Also, theconnection of the blocking signal to terminal 1 of integrated circuit 42serves to block or prevent operation of the circuit to provide an outputat line 43, regardless of the signal at input 42. u

If the transmission characteristic of the key member is greater thanthat of the properly coded key member, more radiation arrives at thesensor 29, the photocell resistance goes down and the, voltage atterminal 2 of integrated circuit 52 goes up or positive. This does notaffect integrated circuit 52, however placing the positive voltage atinput terminal 4 of integrated circuit 42 blocks or prevents operationof the circuit 42 so that there is no access signal on output line 43regardless of the. signal at input terminal 42.

Even if the average transmission characteristic of the key membermatches that of a properly coded key member, access cannot be obtainedif the transparency of the keymember is not a complement of thetransparency of the receptacle. When the transparencies are notcomplements, there will be some light transmission to the photocell 28and the voltage at terminal'2of integrated circuit 42 will not gosufficiently negative to trigger an output. Hence it is seen that accesscannot be obtained by inserting a completely opaque key member. Thistype of key member would provide the proper signal at terminal 2 ofcircuit 42, but the circuit 42 would be blocked by the output-from thesensor 29 in the manner described above.

A time delay may be used with the units 42 and 52 so that once thecircuit has been triggered to provide an output, this output will bemaintained for a preset length of time. Typically the time is severalminutes and permits the person with the properly coded key member toremove the key member and perform other acts such as opening a door,entering a building and deactivating an alarm system within thepermitted time interval. The time delay may be obtained by means of atypical RC circuit, as by connecting a resistor 55 between terminals 8and 6, 7, and a capacitor 56 between terminal 6, 7 and circuit ground ofunit 42. A similarRC circuit may be used for the unit 52.

Although an exemplary embodiment of the invention has been disclosed anddiscussed, it will be understood that other applications of theinvention are possible and that the embodiment disclosed may besubjected to various changes, modifications, and substitutions withoutnecessarily departing from the spirit of the invention.

'I claim:

1. In an access control system, the combination of:

a receptacle having a first station and a second station and includingmeans defining a slot for receiving a key member for movement past saidfirst station to said. second station;

a first radiation sensor mounted at said first station;

a second radiation sensor mounted at said second station;

means for directing radiation across said slot to each of said sensors;

a first transparency mounted at said first station; and

a key member having a second transparency which is the complement ofsaid first transparency, with said second transparency positioned onsaid key member to move past said second station to said .first stationas said key member is inserted into said slot, and with at least theportions of said key member which are at said second station duringinsertion having an average radiation transmission characteristicsubstantially the same as that of said second transparency.

2. A system as defined in claim 1 wherein said transparencies are aphotographic positive and a photographic negative.

3. A system as defined in claim 2 wherein said key member is a strip ofphotographic film with said second transparency a part thereof.

4. A system as defined in claim 1 wherein said receptacle includesspaced plates providing said slot therebetwe'en, each of said plateshaving an opening at said first stationand at saidsecond station forreceiving said sensors and a radiation source.

'5. A system as defined in claim 1 including:

a first detector having an input and an output; and

first circuit means connecting said first sensor to said first detectorinput, with said first detector providing an access signal at the outputthereof when a complementary second transparency is opposite said firsttransparency blocking substantially all radiation to said first sensor.

6. A system as defined in claim 5 including:

a second detector having an input and an output,

second circuit means connecting said second sensor to said seconddetector input, with saidsecond detector providing a blocking signal atthe output thereof when a key member having an average radiationtransmission characteristic substantially different from that of saidfirst transparency is positioned at said second station; and

third circuit means connecting said blocking signal to said firstdetector for blocking any access signal output.

7. A system as defined in claim 6 with said second circuit means alsoconnecting said second sensor to said first detector, with said seconddetector providing said blocking signal when said key member averagetransmission is less than that of said first transparency. and with thesignal from said second sensor providing a tion of said device by anaccess signal.

P ATENT NO. 1 3,896,345 I I DATED ul zz, 1975 UNITEDISTATES PATENTANDITRADEMARK OFFICE 1 I CERTIFICATE CORRECTION INVVENTOR(S)YI Henry R.Zink It is certifiedihafrror appears in th'abov-identified patntahd thats aid L etters Pat ent are hereby corrected as shown blow:

"'[SEALI [76] InventorsaddreS, Z:i.p179 2352 should be 934S2--- 7 Column,1 line-8 "3,773,862" should be '--s, 733,862-- Column 1, line 21 "numbef should be -'-member-- also.

Column 2, line 30. V I I r I I I Bignc d and Blcld this I fourze er ithDay of '0 ctobe r 1975 A ttest:

RUTH C. MASON I I C. MARSHALL DAN'N Arresting Officer Commissioneruflarents and Tr ailema rks UNITED STATES PATENT AND TRADEMARK OFFICECETIFICATE OF CORRECTION PATENT NO. 3,896,345 DATED July 22, 1975 lN\/ENTOR(S) Henry R. Zink It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

[76] Inventor's address, Zip "92352" should be "93452-- Column 1, line 8"3,773,862" should be --3,733,862-- Column 1., line 21 "number" shouldbe --member-- also Column 2, line 30.

Signed and Sealed this fourteenth Day of Oct0ber1975 [SEAL] A tteSt.

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parentsand Trademarks

1. In an access control system, the combination of: a receptacle havinga first station and a second station and including means defining a slotfor receiving a key member for movement past said first station to saidsecond station; a first radiation sensor mounted at said first station;a second radiation sensor mounted at said second station; means fordirecting radiation across said slot to each of said sensors; a firsttransparency mounted at said first station; and a key member having asecond transparency which is the complement of said first transparency,with said second transparency positioned on said key member to move pastsaid second station to said first station as said key member is insertedinto said slot, and with at least the portions of said key member whichare at said second station during insertion having an average radiationtransmission characteristic substantially the same as that of saidsecond transparency.
 2. A system as defined in claim 1 wherein saidtransparencies are a photographic positive and a photographic negative.3. A system as defined in claim 2 wherein said key member is a strip ofphotographic film with said second transparency a part thereof.
 4. Asystem as defined in claim 1 wherein said receptacle includes spacedplates providing said slot therebetween, each of said plates having anopening at said first station and at said second station for receivingsaid sensors and a radiation source.
 5. A system as defined in claim 1including: a first detector having an input and an output; and firstcircuit means connecting said first sensor to said first detector input,with said first detector providing an access signal at the outputthereof when a complementary second transparency is opposite said firsttransparency blocking substantially all radiation to said first sensor.6. A system as defined in claim 5 including: a second detector having aninput and an output; second circuit means connecting said second sensorto said second detector input, with said second detector providing ablocking signal at the output thereof when a key member having anaverage radiation transmission characteristic substantially differentfrom that of said first transparency is positioned at said secondstation; and third circuit means connecting said blocking signal to saidfirst detector for blocking any access signal output.
 7. A system asdefined in claim 6 with said second circuit means also connecting saidsecond sensor to said first detector, with said second detectorproviding said blocking signal when said key member average transmissionis less than that of said first transparency, and with the signal fromsaid second sensor providing a blocking signal when said key memberaverage transmission is greater than that of said first transparency. 8.A system as defined in claim 6 wherein each of said first and secondcircuit means includes a variable resistor in series with the sensor forconnection across a voltage source, with the junction of the sensor andvariable resistors connected to the detector input.
 9. A system asdefined in claim 5 including an access control device and meansconnecting said first detector output to said device in controllingrelation for actuation of said device by an access signal.